GIS经纬度坐标转换为unity3D的世界坐标

GIS经纬度坐标代表现实生活中地球的经纬度坐标，具体代码如下：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GisPointTo3DPoint : MonoBehaviour {

    public static GisPointTo3DPoint Instance = null;

    public Transform firstPoint; //Unity中右下点  
    public Transform secondPoint;//Unity中左上点  

    private Vector2 firstSai;//地图中对应的左上经纬度点  
    private Vector2 secondSai;//地图中对应的右下经纬度点  

    private float z_offset, x_offset, z_w_offset, x_w_offset;

    private RaycastHit rayHit;

    // Use this for initialization  
    private void Start()
    {
        if (Instance == null) Instance = this;
        else if (Instance != this) Destroy(this);

        InitBasicNum();//初始化参数  
    }

    // Update is called once per frame  
    private void Update()
    {
        //if (Input.GetMouseButton(0) && Physics.Raycast(Camera.main.ScreenPointToRay(Input.mousePosition), out rayHit, Mathf.Infinity))
        //{
        //    print(getWorldPoint(new Vector2(113.94495f, 22.52078f)).x + "," + getWorldPoint(new Vector2(113.94495f, 22.52078f)).z);
        //    //print(getLatLon(rayHit.point).x + "         " + getLatLon(rayHit.point).y);
        //}
    }

    private void InitBasicNum()
    {
        firstSai = new Vector2(113.94187f, 22.52283f);
        secOndSai= new Vector2(113.94797f, 22.51844f);

        z_offset = Mathf.Abs(firstSai.y - secondSai.y);//地图中的维度差  
        x_offset = Mathf.Abs(firstSai.x - secondSai.x);//地图中的经度差  

        z_w_offset = Mathf.Abs(firstPoint.localPosition.z - secondPoint.localPosition.z);//unity中的维度差  
        x_w_offset = Mathf.Abs(firstPoint.localPosition.x - secondPoint.localPosition.x);//unity中的经度差  
    }

    public Vector3 getWorldPoint(Vector2 se)//由经纬度得到位置点  
    {
        float tempX = Mathf.Abs(se.x - secondSai.x);
        float tempZ = Mathf.Abs(se.y - firstSai.y);

        float _tempX = (tempX * x_w_offset / x_offset + secondPoint.localPosition.x);
        float _tempZ = (tempZ * z_w_offset / z_offset + firstPoint.localPosition.z);

        return new Vector3(_tempX, 0f, _tempZ);
    }

    public Vector3 getLatLon(Vector3 curPoint)//由位置点得到经纬度  
    {
        float _z_offset = Mathf.Abs(curPoint.z - secondPoint.localPosition.z) * z_offset / z_w_offset;
        float _x_offset = Mathf.Abs(curPoint.x - firstPoint.localPosition.x) * x_offset / x_w_offset;

        float resultX = _x_offset + firstSai.x;
        float resultZ = _z_offset + secondSai.y;

        return new Vector2(resultX, resultZ);
    }
}